Negative Discharge Research Articles

A diffuse argon plume generated downstream of an atmospheric pressure plasma jet equipped with a positively biased electrode

Compared with the diffuse mode of helium plasma jets, a filamentary mode is normally produced in the plasma plume with less expensive inert gas, such as argon, which is undesirable because intense discharge in the filamentary mode may cause damage to fragile samples. Many efforts have been attempted to realize the diffuse mode of an argon plasma jet. In this paper, the diffuse mode is realized in an atmospheric pressure argon plasma jet with increasing biased voltage (V b) applied to a downstream plate electrode. Results show that the diffuse mode transits from the filamentary mode with the increase of V b. Waveforms of voltage, current and integrated light emission reveal that the filament originates from a positive discharge with a needle anode, while the diffuse mode results from negative discharges with a needle cathode, which consist of a Trichel-pulse phase and a slower-varying phase. By fast photography, the positive discharge is attributed to a streamer regime, whereas the negative discharges belong to a Townsend-discharge regime. From optical emission spectroscopy, electron density, electron excitation temperature, vibrational temperature, and rotational temperature are studied as functions of V b.

A compound plume with solid and hollow parts formed downstream of an argon plasma jet at atmospheric pressure

Plasma jet is able to produce abundant active species in plasma plume, whose morphology is a key issue for its various application fields. In this paper, we report the first observation of a compound plume with a solid part and a hollow one in an argon plasma jet. Results indicate that the compound plume can only be formed under proper conditions. Integrated emission waveform reveals that the compound plume initiates with periodicity. By fast photography, it is found that after a passage of straight-line propagation, some positive discharges behave as a curved propagation due to the influence of residual ions. Moreover, the solid part comes from negative discharges and the straight-line propagation of positive discharges. In contrast, the hollow part originates from the curved propagation of positive discharges. Optical emission spectroscopy verifies the existence of residual ions. These results can enrich the morphology of plasma plume.

Ballooning instability preventing the H-mode access in plasmas with negative triangularity shape on the DIII–D tokamak

Infinite toroidal mode number (n = ∞) ballooning mode analysis of negative triangularity discharges on DIII–D shows that the access to 2nd stability becomes strongly restricted when the top triangularity decreases even modestly from −0.18 to −0.36. This is observed in experiment to coincide with the suppression of the L–H-transition. Further theoretical analysis with ballooning mode limited pedestals shows that the threshold for opening the 2nd stability access rises from a pedestal temperature of 0.3–1 keV when the top triangularity is decreased from −0.18 to −0.36 indicating that to access the 2nd stability with the more negative triangular shape would require unrealistically high pedestal temperature. The pedestal predicted by the EPED code agrees with the experimental H-mode profile for the negative triangularity case but in contrast to positive triangular shapes the prediction shows no increase in pedestal height with increasing core pressure when triangularity is negative. This work provides a first model to predict when negative triangularity plasmas can be expected to access the H-mode.

Inactivation of Acanthamoeba Cysts in Suspension and on Contaminated Contact Lenses Using Non-Thermal Plasma.

Water suspensions of cysts of a pathogenic clinical isolate of Acanthamoeba sp. were prepared, and the cysts were inactivated either in suspension or placed on the surface of contact lenses by the non-thermal plasma produced by the DC corona transient spark discharge. The efficacy of this treatment was determined by cultivation and the presence of vegetative trophozoites indicating non-inactivated cysts. The negative discharge appeared to be more effective than the positive one. The complete inactivation occurred in water suspension after 40 min and on contaminated lenses after 50 min of plasma exposure. The properties of lenses seem to not be affected by plasma exposure; that is, their optical power, diameter, curvature, water content and infrared and Raman spectra remain unchanged.

Buck and Boost Inverter

Abstract: A versatile operation of any electronic circuitry depends on the power source supplying the power for its operation. The buck converter is implemented using an integrated circuit(IC), LM317. The constructed buck converter was tested for load and line regulation cited in the datasheets for stability. The test and analysis for the linear buck converter was done using setup. The output measurements indicate that the power supply is functional. The measured output values results of the test circuit. The developed output power supply unit is important in measurements, laboratories and test setup. It is implemented for all general applications that require power supply unit. XL6009 module is a DC to DC BUCK-BOOST converter module that operates at a switching frequency of 400kHz. In such high frequency, it provides smaller sized filter components compared with low frequency switching regulators. An improved SingleStage Buck-Boost inverter is provided, using only three or four power semiconductor switches. The inverter can handle a wide range of dc input voltages and produce a fixed ac output voltage. The inverter is well suited to distributed power generation systems such as photovoltaic and wind power and fuel cells, for standalone or grid connected applications. The inverter has a single charge loop, a positive discharge loop and a negative discharge loop. In this complete design of the converter is carried out. This application report gives details regarding this conversion with examples

A DESCRIPTIVE STUDY OF BACTERIOLOGICAL SPECTRUM OF ORTHOPEDIC IMPLANT INFECTION IN CLOSED FRACTURES

Background- Surgical Site Infection (SSI) is defined as pain associated with erythema, induration, local tenderness, pus discharge or any culture positive or negative discharge from a surgically created wound.
 Methods- Descriptive type of Observational study conducted on Patients in the department of Orthopaedics.
 Results- 6.00% patients have wound infection. Gram positive 83.33% patients have found with Staph. Aureus and Gram- negative 16.67% patients have found with Pseudomonas.
 Conclusion- Infection in closed fractures with implants was quite high. The adverse outcome of SSIs related to a clean orthopedic surgical procedure can be associated with significant morbidity, cost, and even mortality.
 Keywords- SSI, Closed, Implants

Discharge characteristics and reactive species production of unipolar and bipolar nanosecond pulsed gas–liquid discharge generated in atmospheric N2

In this paper, unipolar pulse (including positive pulse and negative pulse) and bipolar pulse voltage are employed to generate diffuse gas–liquid discharge in atmospheric N2 with a trumpet-shaped quartz tube. The current–voltage waveforms, optical emission spectra of excited state active species, FTIR spectra of exhaust gas components, plasma gas temperature, and aqueous H2O2, and production are compared in three pulse modes, meanwhile, the effects of pulse peak voltage and gas flow rate on the production of reactive species are studied. The results show that two obvious discharges occur in each voltage pulse in unipolar pulse driven discharge, differently, in bipolar pulse driven discharge, only one main discharge appears in a single voltage pulse time. The intensities of active species (OH(A), and O(3p)) in all three pulsed discharge increase with the rise of pulse peak voltage and have the highest value at 200 ml min−1 of gas flow rate. The absorbance intensities of NO2 and N2O increase with the increase of pulse peak voltage and decrease with the increase of gas flow rate. Under the same discharge conditions, the bipolar pulse driven discharge shows lower breakdown voltage, and higher intensities of excited species (N2(C), OH(A), and O(3p)), nitrogen oxides (NO2, NO, and N2O), and higher production of aqueous H2O2, and compared with both unipolar positive and negative discharges.

A DESCRIPTIVE STUDY OF BACTERIOLOGICAL SPECTRUM OF ORTHOPEDIC IMPLANT INFECTION IN CLOSED FRACTURES

Background: Surgical Site Infection (SSI) is defined as pain associated with erythema, induration, local tenderness, pus discharge or any culture positive or negative discharge from a surgically created wound.
 Methods: Hospital based Descriptive type of Observational study conducted on Patients in the department of Orthopaedics in teaching hospitals attached to S.M.S Medical College and hospital.
 Results: 6.2% patients have wound infection. Gram positive 87.5% patients have found with Staph. Aureus and Gram negative 12.5% patients have found with Pseudomonas.
 Conclusion: Infection in closed fractures with implants was quite high. Th e adverse outcome of SSIs related to a clean orthopedic surgical procedure can be associated with significant morbidity, cost, and even mortality.
 Keywords: Infection, Closed, Implants

High-Frequency Oscillations on Interictal Epileptiform Discharges in Routinely Acquired Scalp EEG: Can It Be Used as a Prognostic Marker?

IntroductionDespite all the efforts for optimizing epilepsy management in children over the past decades, there is no clear consensus regarding whether to treat or not to treat epileptiform discharges (EDs) after a first unprovoked seizure or the optimal duration of therapy with anti-seizure medication (ASM). It is therefore highly needed to find markers on scalp electroencephalogram (EEG) that can help identify pathological EEG discharges that require treatment.Aim of the studyThis retrospective study aimed to identify whether the coexistence of ripples/high-frequency oscillations (HFOs) with interictal EDs (IEDs) in routinely acquired scalp EEG is associated with a higher risk of seizure recurrence and could be used as a prognostic marker.Methods100 children presenting with new onset seizure to Children’s Medical Center- Dallas during 2015–2016, who were not on ASM and had focal EDs on an awake and sleep EEG recorded with sample frequency of 500 HZ, were randomly identified by database review. EEGs were analyzed blinded to the data of the patients. HFOs were visually identified using review parameters including expanded time base and adjusted filter settings.ResultsThe average age of patients was 6.3 years (±4.35 SD). HFOs were visually identified in 19% of the studied patients with an inter-rater reliability of 99% for HFO negative discharges and 78% agreement for identification of HFOs. HFOs were identified more often in the younger age group; however, they were identified in 11% of patients >5 years old. They were more frequently associated with spikes than with sharp waves and more often with higher amplitude EDs. Patients with HFOs were more likely to have a recurrence of seizures in the year after the first seizure (P < 0.05) and to continue to have seizures after 2 years (P < 0.0001). There was no statistically significant difference between the two groups with regards to continuing ASM after 2 years.ConclusionIncluding analysis for HFOs in routine EEG interpretation may increase the yield of the study and help guide the decision to either start or discontinue ASM. In the future, this may also help to identify pathological discharges with deleterious effects on the growing brain and set a new target for the management of epilepsy.

Probable Causes and Risk Factors for Positive SARS-CoV-2 Testing in Recovered Patients: Evidence From Guangzhou, China.

Some patients retested positive for SARS-CoV-2 following negative testing results and discharge. However, the potential risk factors associated with redetectable positive testing results in a large sample of patients who recovered from COVID-19 have not been well-estimated. A total of 745 discharged patients were enrolled between January 30, 2020, and September 9, 2020, in Guangzhou, China. Data on the clinical characteristics, comorbidities, drug therapy, RT-PCR testing, and contact modes to close contacts were collected. Patients who tested positive for SARS-CoV-2 after discharge were confirmed by guidelines issued by China. The repositive rate in different settings was calculated. Among 745 discharged patients, 157 (21.1%; 95% CI, 18.2–24.0%) tested repositive and the repositive rate was 16.8% (95% CI, 14.1–24.0%) for nasopharyngeal swabs and 9.7% (95% CI, 7.0–12.5%) for anal swabs. Among them, 55 (35.0%) were asymptomatic, 15 (9.6%) had mild symptoms, 83 (52.9%) had moderate symptoms, and 4 (2.6%) had severe symptoms at the first admission. The days from discharge to repositivity was 8.0 (IQR, 8.0–14.0). Most repositive patients were without clinical symptoms, and lymphocyte cell counts were higher than before being discharged. The likelihood of repositive testing for SARS-CoV-2 RNA was significantly higher among patients who were of younger age (OR, 3.88; 95% CI, 1.74–8.66, 0–17 years old), had asymptomatic severity (OR, 4.36; 95% CI, 1.47–12.95), and did not have clinical symptoms (OR, 1.89; 95% CI, 1.32–2.70, without fever). No other positive patients emerged within the families or close contacts of repositive patients. Our findings support prolonged but intermittent viral shedding as the probable cause for this phenomenon; we need to familiarize with the possibility that the virus will remain endemic.

The acceleration of water absorption time in natural silk fabrics (Bombyx Mori) irradiated with positive and negative corona plasma discharges at atmospheric pressure

This study aims to examine the acceleration of water absorption time in natural silk fabric irradiated with negative and positive corona plasma discharge generation at atmospheric pressure. The point-to-plane electrode configuration is made by one hundred point electrodes, equally distributed, in a 10 x 10 square plane and a plane electrode made of copper. The positive plasma discharge is generated by connecting the point electrodes to a high voltage power supply. In contrast, the negative plasma discharge is generated by connecting the power supply to the plane electrode. During the plasma discharge irradiation, the dyeing natural silk (Bombyx Mori) samples are placed on the plane electrode with varying irradiation duration and electrode spacing. Identification of irradiation effects on the fabrics was made using water drop test and SEM (Scanning Electron Microscope). Increasing the electrode’s gap improves the stability of the corona discharge by reducing the discharge current. Moreover, longer irradiation time results in faster water absorption due to a significant interaction between the torn fabrics and water, especially at a broader electrode gap. In conclusion, both positive and negative corona plasma discharges irradiation alters water absorption time, with longer irradiation time results in faster water absorption by samples.

Study of the characteristic differences of positive and negative half-cycles from atmospheric pressure glow discharge driven by resonant AC voltage

There are many advantages in obtaining low-temperature plasmas that are rich in active particles by atmospheric pressure glow discharge, so there has been a lot of research on the acquisition method and application of it. However, there is a lack of knowledge about the mechanism of atmospheric pressure glow discharge driven by an AC resonant power supply. In this paper, we describe our study of the characteristic differences between half-cycle positive and negative atmospheric pressure glow discharges driven in open air by an AC resonant power supply, and we describe our analysis of the associated physical mechanism. The comparison and analysis of experimental results indicate that both positive-cycle and negative-cycle discharges led to typical glow discharge and no streamer discharge appeared in the discharge process. There were still charged particles in the discharge channel when the discharge current was zero. With increasing amplitude of the output voltage of the power supply, the glow area near the electrode surface and the plasma distribution area in the discharge channel increased. When the output voltage of the power supply was low, the negative polarity discharge was more likely to form in the gap of the pin-to-plate electrode. In the AC discharge process, the α-mode discharge was dominant, and the developing speed of the positive-cycle discharge was faster than that of the negative-cycle discharge. The polarity effect became less obvious with the increase in the output voltage amplitude of the power supply.

Verona Integron-Encoded Metallo-Beta-Lactamase (VIM)–Producing Pseudomonas aeruginosa Outbreak Associated with Acute Care

Background: Contaminated healthcare facility plumbing is increasingly recognized as a source of carbapenemase-producing organisms (CPOs). In August 2019, the Tennessee State Public Health Laboratory identified Tennessee’s twelfth VIM-producing carbapenem-resistant Pseudomonas aeruginosa (VIM-CRPA), from a patient in a long-term acute-care hospital. To determine a potential reservoir, the Tennessee Department of Health (TDH) reviewed healthcare exposures for all cases. Four cases (33%), including the most recent case and earliest from March 2018, had a history of admission to intensive care unit (ICU) room X at acute-care hospital A (ACH A), but the specimens were collected at other facilities. The Public Health Laboratory collaborated with ACH A to assess exposures, perform environmental sampling, and implement control measures. Methods: TDH conducted in-person infection prevention assessments with ACH A, including a review of the water management program. Initial recommendations included placing all patients admitted to room X on contact precautions, screening for CPO on room discharge, daily sink basin and counter cleaning, and other sink hygiene measures. TDH collected environmental and water samples from 5 ICU sinks (ie, the handwashing and bathroom sinks in room X and neighboring room Y [control] and 1 hallway sink) and assessed the presence of VIM-CRPA. Moreover, 5 patients and 4 environmental VIM-CRPA underwent whole-genome sequencing (WGS). Results: From February to June 2020, of 21 patients admitted to room X, 9 (43%) underwent discharge screening and 4 (44%) were colonized with VIM-CRPA. Average room X length of stay was longer for colonized patients (11.3 vs 4.8 days). Drain swabs from room X’s bathroom and handwashing sinks grew VIM-CRPA; VIM-CRPA was not detected in tap water or other swab samples. VIM-CRPA from the environment and patients were sequence type 253 and varied by 0–13 single-nucleotide variants. ACH A replaced room X’s sinks and external plumbing in July. Discharge screening and contact precautions for all patients were discontinued in November, 5 months following the last case and 12 consecutive negative patient discharge screens. Improved sink hygiene and mechanism testing for CRPA from clinical cultures continued, with no new cases identified. Conclusions: An ICU room with a persistently contaminated sink drain was a persistent reservoir of VIM-CRPA. The room X attack rate was high, with VIM-CRPA acquisition occurring in &gt;40% of patients screened. The use of contaminated plumbing fixtures in ACH have the potential to facilitate transmission to patients but may be challenging to identify and remediate. All healthcare facilities should follow sink hygiene best practices.Funding: NoDisclosures: None

Time-resolved analysis of negative pulsed discharges in water: streamer initiation and propagation modes

Analyses of the initiation and propagation-mode transitions of negative streamers are essential to develop a thorough understanding of underwater pulsed discharges. This paper presents experimental observations of negative streamers in deionized water performed using time-resolved visualization and electrical measurements. Based on the distributions of discharge inception delay and quantitative calculations of the ionization initiation fields, a streamer initiation model combining Zener ionization and field emission processes is proposed to account for discharges with short inception delays (<200 ns). Joule heating is the main mechanism responsible for discharges with an inception delay on the order of microseconds. The evolutions of bushy streamer morphology show that streamers exhibit more uniform structures under higher voltages, as most of the streamer branches grow simultaneously. A large-area discharge of bushy streamers is observed and is speculated to be closely related to the charge dynamics at the gas/liquid interface. The propagation of filamentary streamers and the transitions from filamentary to bushy streamers are presented. The redistribution of deposited charge and mitigation of the electric field during branching are the main causes for the mode transitions of streamers.

Optical characterization of miniature flexible micro-tube plasma (FμTP) ionization source: A dielectric guided discharge

Miniature DBD has been obtaining more and more attention. A recently developed miniature flexible micro-tube plasma (FμTP) has proved to be an excellent soft ionization source for mass spectrometry and ion mobility spectrometry. In this paper, the optical characterization of the novel FμTP ionization source was carried out, aiming to cast light on the plasma propagation mechanism in one discharge cycle. To provide a clean environment for investigating the plasma propagation, the plasma was totally sustained in a capillary tube. It was found that in one discharge cycle, three discharge developments, namely two dielectric guided discharges in both positive and negative half cycle, and a negative glow discharge in the negative half cycle. Compared with the conventional dielectric barrier discharge, there is no formation of a dissociative plasma, which improves the soft ionization capacity of the present source. In addition to the whole light emission from 200 nm to 1100 nm, the lines related to the reactive species including He 706 nm, N2+ 391 nm, and O 777 nm were investigated spatially and temporally. Due to the effect of the attached charges, the plasma of the negative half cycle propagates faster than that of the positive half cycle. It was also found that the plasma in the positive half cycle propagates more discretely than that of the negative one, while the negative one has a larger emission intensity due to the overlap of the signal in both temporal and spatial scales. Further on, the electric field distribution was proved to be in Gaussian shape along the diameter of the capillary, while the negative one has a flat shape. By changing the concentration of N2 in He, the electron collision and penning ionization for generating N2+ were experimentally proved and identified. This study identifies the typical discharge process of the FμTP in one discharge cycle, indicating the plasma is indeed a dielectric guided discharge.

Regional variation of electrical and lightning properties of thunderclouds during the pre-monsoon season over the north-eastern and eastern part of India

Regional variation of electrical and lightning properties of thunderclouds is investigated by using simultaneous observations of electric field mill (EFM-100) and lightning detector (LD-350) in synergy with their radiance and bulk microphysical properties. The study is carried out over Kohima in the north-eastern and over Rampurhat in the eastern part of India (20o-30o N, 85o-96o E), during the pre-monsoon season (March–May) of 2017–2018. The occurrence of EFM-100 detected thunderclouds is found to be more over Kohima (111) compared to Rampurhat (88). Whereas, the average number of lightning flash is much higher over Rampurhat (~542 flash/thundercloud) compared to Kohima (~32 flash/thundercloud). Over both the regions, the maximum occurrence of thunderclouds is found during afternoon to evening hours. The upper whisker value in the box plot shows that thunderclouds over Rampurhat are associated with higher CAPE value (Kohima: 1100 J Kg−1; Rampurhat: 5000 J Kg−1). The diurnal variation of CAPE supports relatively early occurrence of thunderclouds over Kohima. Thunderclouds over Rampurhat persists for relatively longer duration. It is observed that overall percentage occurrence of CG lightning is more over Kohima (Kohima: −CG: 28.09% & +CG: 09.74%; Rampurhat (–CG: 12.33% & +CG: 08.60%), with relatively higher −CG lightning compared to +CG, over both the stations. On the contrary, the occurrence of IC lightning is more over Rampurhat (Rampurhat: −IC: 31.75% & +IC: 47.30%; Kohima: −IC: 36.44% & +IC: 25.72%). Over Kohima occurrence of −IC is more than the +IC, whereas over Rampurhat, the occurrence of +IC is more than −IC. The overall higher occurrence of total negative and positive discharges over Kohima and Rampurhat respectively is consistence with EFM observations. The prevalence of positive/negative discharge suggests the presence of a tripole charge structure within thunderclouds over both the regions. The upper whisker value in the box plots revels higher CG flash density, IC:CG and larger log(area) over Rampurhat (Kohima: 3.0 × 10−3 flash km−2 h−1 and Rampurhat: 4.25 × 10−3 flash km−2 h−1; Kohima: 7 and Rampurhat: 15; Kohima: 10.5 km2 and Rampurhat: 11.5 km2). The lower whisker value of cloud top temperature reveals prevalence of colder thunderclouds over Rampurhat (Kohima: 220 K; Rampurhat: 184 K). The thunderclouds over Rampurhat are found to be associated with stronger updrafts and mixed-phase processes. The study reveals that, over these two regions, the electrical and lightning properties have distinct characteristics.

Study on electrolyte additives of water-based magnesium batteries

The effects of different inorganic salt additives on the corrosion resistance, hysteretic behavior and activation potential of magnesium anode in MgSO4-Mg(NO3)2 composite electrolyte (1.86 mol·L-1 Mg(NO3)2 + 0.14 mol·L-1 MgSO4) were compared by electrochemical method. The electrochemical test results showed that in the solution containing 0.02 mol/L NaHCO3, the activation potential of magnesium anode was the most positive, the passivation range was expanded, and the polarization current was reduced. The impedance of magnesium alloy with 0.02 mol/L NaHCO3 has the highest corrosion resistance, which is consistent with the conclusion that the corrosion current density of Tafel polarization curve is the lowest. Under the additive concentration, the magnesium anode has the shortest lag time, the most negative discharge potential and the least potential drop, which greatly improve the discharge performance of magnesium anode.

Study on the polarity effect in an atmospheric pressure glow discharge driven by resonant power supply

In recent years, atmospheric pressure glow discharge has become an active research area for many scholars because of its broad industrial application prospects. However, much of the research is focused more on how to acquire this type of discharge or how to use it in some fields; there is a lack of clear and universally accepted theories. In this paper, we described the polarity effect in the process of atmospheric pressure glow discharge driven by a resonant power supply, from the standpoint of the differences in electric field direction in the pin-to-plate gap. We also discussed the characteristics of the discharge waveform, the characteristics of discharge images and the light-intensity distribution on the centerline of the discharge channel. Also studied were the polarity effect of unipolar discharge and the influence of different output-voltage amplitudes on the polarity effect. We found that both positive and negative discharges looked like a typical glow discharge. The voltage and current waveforms of unipolar discharge have a rapidly rising slope, and there is strong ionization near the anode. In the process of a unipolar discharge, there is an obvious γ discharge stage, and the α mode discharge has an obvious high-slope stage, whereas the slope of this process of a negative discharge is more gradual, and the polarity effects of positive and negative unipolar discharges become less and less obvious with the increase in the output-voltage amplitude of power supply.

The effect of silica content to partial discharge characteristic of low-density polyethene and natural rubber blend as the electrical insulator

The dielectric properties of low-density polyethylene natural rubber (LDPE-NR) biopolymeric insulating materials can be improved by adding the silica nanoparticles in a certain percentage of weight (w%). In the present study, four types of bio-nano polymeric samples were prepared. To each sample, the nanosilica particles with wt% 1.5%, 3%, 4.5% and 6%. As one characteristic of dielectric, the partial discharge (PD) characteristics, each sample has been tested for 1 hour under AC high voltage field, and the pulses were counted for each sample and grouped into positive and negative pulses. The PD pattern was also plotted based on X-Y axes, namely Φ-q-n pattern. It was found that the number of positive and negative partial discharge (PD) pulses for each silica sample after 60 minutes of testing varied for all samples. It is also found that samples with a higher percentage of nanosilica had fewer PD pulses. The PD pattern in lower w% of silica was identified in the 90 degrees mostly in containing This indicates that w% of nanosilica particles can improve the PD resistance or the insulation quality of LDPE-NR insulation materials.

Atmospheric diffuse plasma jet formation from positive-pseudo-streamer and negative pulseless glow discharges

Atmospheric gas discharge is very likely to constrict into filaments and diffuse plasma formation is inefficient in most cases. Developing cost-efficient atmospheric diffuse plasma devices represents a significant challenge for high performance in biomedical decontamination and material processing. Here, we propose an alternative roadmap to produce a diffuse argon plasma jet by expanding and quenching the existing filamentary discharge at the initial or middle stage of streamer development. Possible mechanisms are summarized. With the gas flow velocity comparable to the ion drift one, enhancing ambipolar diffusion near the edge of the positive-streamer channel promotes the radial diffusion of newly-produced electrons, realizing the radial expansion of channel. Weakening electric field in front of the streamer head through head expansion and field offset, prevents the further development of streamer, leading to a positive-pseudo-streamer discharge. Reducing electric field in front of the negative-streamer head through ion compensation, impedes the initial growth of streamer, resulting in a negative pulseless glow discharge. The positive-pseudo-streamer and negative pulseless glow discharges function together to form the diffuse plasma jet.